网站简介：Astronomical observation planning, logging, reporting, and telescope control software for imagers and visual observers.
网站简介：Provides an introduction to satellite viewing and information on the many satellites in orbit.
网站简介：A guide to give a tour of the summer night sky.
网站简介：Works to maintain the International Celestial Reference System and Frame, and the International Terrestrial Reference System and Frame, and to provide timely and accurate data on the Earth's orientation for current use and long-term studies. Site describes the group's structure and function.
网站简介：Calculates sun position and plots shadows cast by the sun over any chosen location, with drawing tools to construct your own scene and automatically plot the shadow results.
网站简介：From the U.S. Naval Observatory. Online forms provide sunrise, sunset, moonrise, moonset, and twilight times for one day or one year; moon phases, eclipse charts, and data for major solar system bodies and bright stars.
网站简介：Japanese manufacturer of planetariums and telescopes. [Spanish, English, Japanese]
网站简介：JavaScript calculator of sizes and distances of solar system bodies for making a scale model.
网站简介：Calendar, special events, newsletter, articles, photography, and classifieds located in Suffern..
网站简介：Non-profit, state funded Italian research institute devoted to Astronomy and Astrophysics. Page contains list of activities, public outreach, seminars, thesis, and resources.
网站简介：Sells telescopes and accessories. Online catalog, tips and information about workshops and star parties.
网站简介：From The Nine Planets.
网站简介：Overview with data, text, images, links.
网站简介：General information, equipment and instruments, observer information, resources, and education and outreach.
网站简介：Interactive planetarium that can produce maps for any time and date, viewpoint, and observing location.
网站简介：USA based manufacturer of 2" Binoviewers, 1.25" Binoviewers, high quality eyepieces, telecentric and regular Barlows and other telescope accessories.
网站简介：Show schedule, Challenger Learning Center, links, teacher information, community learning, and programs and events.
网站简介：Apochromatic refractor and Maksutov-Cassegrain telescopes plus precision optics including optical flats, Cassegrain, Catadioptric, Newtonian, Ritchey-Chretein, Mersen and other optical designs.
网站简介：Chinese manufacturer and exporter of binoculars, telescopes, monoculars, golfscopes and spotting scopes.
网站简介：Manufactures Ritchey Chretien, APO and Super APO optics, complete RC and refractor OTAs, Dobsonian telescopes, plus professional and custom instrumentation.
网站简介：Views from the space, animations, general information and data.
网站简介：Produces the MaxCam and IMG series CCD cameras for astronomical applications, color filter wheels, DF2 digital focuser and research grade filters.
网站简介：Lists the group members and research activities of the group with links to more information.
网站简介：Archives astronomical data. Includes star dates, comets, glossary, astronomical catalogs, calendar, meteor events, and astromaps.
网站简介：Contains contact information for many clubs world wide.
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